Lock nut



CJI

igatented May lil, l927.

stares JOHNiIvIADDEN, OF DETROIT, MICH'IGA-N.

Lock Nutr;

Application ined october 30, 19'24; senat-No. -74,'7l

ln the endeavor to [ind suitable means for n the prevenlion or" the loosening or lossl of to which they are applied, a great many suggestions have been otiiered trom time to* some oli which included auxiliary lock4 ing devices applied to thepnuts tor the pur` pose ot ting or pre\ientingtheir reverse rotatior stier application to an article, but such devices according to their nature suflered trom many disadvantages even in those cases Where they very etnciently per Ytorni their locking tunction when once applied, among which disadvai'itages maybe mentioned the following: n

in some cases'the locking oit the nut'shas been ctiected beyond the desired extent' inasn'iuch als it prevented the removal' or loosening or the nuts When it Was desired to dov so, Where yno provision was made to permit the locking devices being. rendered inoperablev or less ei'ective whenr deliberate ref moval or loosening ot the nuts Was required.

The' provision or parts supplementary tof the nuls was also objectionable due to the additional cost of such parts and the possibility ol' loss ot' the saine or injury thereto which would destroy or minimizetheir use iulness and to the fact that they usually nec itated special yprovision of coacting means or devices on the nuts or on the parts adjacent the nuts when in position, Which means were orten in the form ot' notches, holes, projections or latches, adding to the' expense oir' the device, limiting the positions' in which the nuts might be locked, necessitating additional Work on the nuts after their initially complete manufacture, or red :ing the strength, usefulness, or conven-A ience et the nuts due to the presence ot such llUlllS.

Gtaer methods ot providing 'for a loci;-

ing effect in nuts involved the distortion ofv the threads, limiting of the number thereof, the undue increasing ot the dimensions of the nuts, the binding of the nuts upon the part to which they are applied in a manner .tending to result in a destruction of the threads, and also often calling for special threads, thereby complicating the manufacture thereof.

By my invention l propose to provide a lock nut wherein the aforesaid disadvantages are obviated and wherein ease of operation and eifectiveness ot the lookin@ ica ture are secured in a highly advantageous manner Without loss in thenntg y I The invention lfurther aims to provide a two-part lioclr nut having a virtually continuous v thread extending therethrough, whereby full benefit ot' thread engagement is si-icuiedl throughout the combined thickness ot' thev said tivo-part lock nut; a' further and important object being' to provide af lock nut which may be loclred on a threaded stein in any desired position irrespective ot' the provision ol ai juxtaposedv bearing surface Jr'or said lock nut, whereby the said nu't may be secured in engageh'ient with a device from which4 the threaded ystem extends' vor in spaced relation to such5 stem and whereby ot ,mechanical eiiici'ency in the event of the' said lock nut being Ator any reason moved' from its originalV setting on a threaded stem may, by itst'ien'dency to rotate thereon, automati allyreloclritsel't onv the' d sternv and thereby prevent total,l disengagement or loss thereof from the saidl lWherebya double locking effort is attained,

insuring a veryeliicient binding, etl'ect; of the' nut uponk the threaded member which may be very readily brought mto operation irrespectiveot the' position ot the n'ut' on the' saidA threaded member and" which may" be easily overcome by the Adeliberateinanipulation of the' parts' ofthe nut', although not being liable.to release excep't such deliberate manipulation; a still', further object being to provide a vtwo-'part lockl nut Wherein advantage' is taken of the lockingthrust eliected by `the tighteningl ot' one part against a superimposed' part, as in the com'- mon practice ofutiliring'two ordinary nuts, together vrith the utilizing ot an yeccentric engagement between coacting' eccentric faces of the said' parts of thenutxvith consequent assistance in the securing of the parts of the said nut in' their relative l'eking positions.

Still further objects' subsidiary' to ory resulting trom the aforesaid objects, or from the construction or operation ot' tlies'aid'` invention as it may be carried intov effect, ivill become'- 'apparent asthe said invention is hereinafter further disclosed. n i,

-In carrying the said inventfin into effect' l mayl provide a* lock nut which comprises two-parts coaxially and continuously tapped for the reception of a bolt or threaded member, one of the said members being provided with an eccentric cam entering and practically coincident with a corresponding recess in the opposed face of the other of said members and the threads of the said members being arranged in virtual continuity in one position of the members whereby upon the rotation of one of the said members with respect to the other the continuity7 of the said threads will be disturbed as well as the axial alinement thereof due to the eccentric engagement between the members of the nut, and whereby as a result when the said nut is engaged with a threaded member, such olisturbances will result in end thrust between the members against the threads of the threaded member and in side thrust of the members respectively in opposite directions against said threaded member, which disturbances of thread, continuity and alinement, as well as the thrust referred to and the friction set up between the eccentricallj: engaging parts of the nut will result in an effective locking or binding of the said nut on the said threaded member, which may be overcome when desired by the rotation of one of the said members with respect to the other' in a direction and to an extent necessary to reinstate the axial alinement of the members and the relief of the thrust resulting engagement of the eccentric parts of the said members.

All of which is more particularly described and ascertained hereinafter, by way of example, having reference to the accompanying drawings, wherein Figure 1 is a sectional view of a lock nut constructed in accordance with this invention and applied to a threaded member, the relative spacing of the threads and parts of the lock nut being exaggerated for clearness of illustration;

Figure 2 is a section of the same taken on the line 2X- X, Figure 1;

Figure 3 is a similar view to Figure 1, illustrating` in an exaggerated manner the locking action of the said lock nut when the members thereof are rotated relative to one another for that purpose;

Figure 4 is an end elevation of the same;

Figure 5 is a perspective detail view of one of the lock nut members; and

Figure 6 is a perspective detail view of the coacting member.

Similar characters of reference indicate similar parts in the several gures of the drawing. n

1 indicates a bolt, the threads 2 of which have their upper and lower faces indicated by the numerals 3 and 4 for purposes of particular designation in the following explanation of the matter and application of the lool? nut, which comprises upper and lower members 5 and G, respectively, which are coaxially tapped to form threads 7 and 8 in the two parts, the said threads extending virtually continuously through the said members 5 and 6 when they are assembled together in their normal or free position which will be further referred to and explained and which is not illustrated in Figure 1 of the drawing.

For convenience the members are externally of hexagonal or similar configuration, admitting of their being firmly gripped for rotation, and in the normal or free position indicated in Figure 1, the flats of the members are alined so that they presentthe appearance of a single nut split intermediate of its height, the parting being at 9; and to in dicate the correct relationship of the two members, in which the said continuity of the thread exists. said members may be provided with index marks 10 and 11 adapted to be in alinement when the said members are in their free position, or in other words when the said members are in such relative positions that continuity of the threads 7 and 8 exists and the said members may be together freely rotated on the threads of the bolt.

The lower member 6 is shown as having extending upwardly therefrom and circumscribing the threaded bore thereof an eccentric cam 12 which freely enters a correspondingly eccentric recess 13 in the underside of the member 5 when the parts are in the free position .as indicated in Figure 1, a sliding lit being provided between the periphery of the said cam and the surrounding wall of the recess 13. In this free position of the parts the alinement of the threads of the members permits their freely rotatable engagement with the bolt 1 and such rotation may be continued to any desired extent as long as the members are retained in their relative positions with respect to one another as would be the case were they both simultaneously gripped by a wrench when being applied to a bolt or threaded object; but if one of the members be rotated with respect to the other, then the continuity of the threads and 8 would be disturbed so that if the rotation of the one member be in a direction effecting its movement towards the other member, then a binding of the two members upon the bolt er threaded object in the manner well known to mechanics will result, the tl'ireads` of the members 5 and 6 being pressed respectively against the lower and upper surfaces 3 and -lof the thread 2. i

Fowever, in the present case such rotation of one member' with respect to the other also accompanied by the rotation of the cam 12 within its recess and the consequent tendency of the said cam to ride within the walls of the said recess and to throw 'the members out of alinen'ient. rihis action produnes several results' which are illustrated in an exaggerated way in Figure 3, which indicates the members of the lock nut as having been relatively rotated to the extent indicated in Figure Ll, whereby the cam l2 riding against the surrounding wall of the recess 13 has resulted: in a displacement of the upper member towards the left hand side of the figure and of the lower member towards the right hand side of the iigure, as the result of which opposed lateral forces are set up in the tWo members, and aside' thrust exerted in each case in an opposite direction by the said nie-mbers againstv the bolt l, this action being` also combined with the end` thrust referred to bet/Ween the saidl members. The said action' therefore produces ay combination of stresses tending to` frnfcev the threads of the members to assume a position on the thread of the boltsomewhat approximating that illustrated in an exaggerated form in Figure 3, which tendency very effectively binds the lock nut against movement of its bolt.

There is still another factor which enters into the effectiveness of the locking function and that is the frictional engagement Which takes place between the periphery of the cam and the surrounding Wall of the recess 18, which friction binds the members together with a force equal to that resulting in the side thrust of the members upon the bolt, so that there is little liability of the members returning to a free or unlocked position, the throw of the cam being small, although one or other of the said members may be deliberately rotated, such as by the application of a Wrench thereto, in order to bring it into its normal position relative to the other of said members, when they may again both be freely rotated together on their bolt.

As will be understood from Fig. el, the length of the relative angular movement of the tivo nuts in passing from free to locked position or vice versa, is approximately 15. Obviously, the length of such movement on the threads of the bolt is of a similar angle. And since the amount of relative movement of the tivo nuts axially ivill depend upon the pitch of the threads, it will be readily understood that With an angular movement of this length, the axial movement of one nut relative to the other is very small; in fact, they length of axial movement may be found almost Within the limits of the slight play that provided by the male and female threads of the bolt and nuts, so that in actual practice, the nuts are practically in facial contact `when in their free-running position.

There are several positive advantages accrue by reason of this condition. For instance. when the nuts are to be run upon the bolt thread, there is no need for attempting to hold them at an accurately-spaced position, sincel they can be brought into thc facial contact with the index marks alined. and both nuts will freely run on to the bolt threads; where initial spacing is required, it is diiiicultto provide or determine the actual space during the absei'ice of the bolt threads, and the cam conditions prevent rotation of the outer nut to correct lthis condi-I tion. Another advantage results freni the fact that with the facial contact present in the free-running position, relative movement of one nut angularly to the other provides relative movement of the contacting faces, With the thread pitch active to produce the small axial movement ofthe moving nut; hence, the contacting faces coact to provide pressures on the opposite nut, the result loe-- ing that the thrust pressures will tend to force the inner nut inwardly and the outer nut outwardly onto the thread faces, thus setting up the' conditions indicated in Fig. 3, and providing the thread tightening effect throughout the axial length of both nuts, the effect being on one face of the bolt thread in the Zone of one of the nuts, and on the opposite face of the thread in the Zone of the other nut.

The particular shape of the cam and of the surface With Which it coacts its a matter of convenience or desirability, and may be varied to suit manufacturing or other conditions, although, the greater the bearing surface that can be secur-ed, the greater the friction and consequentbinding of the members againstl unlocking, so that an eccentric such as that illustrated is a preferred form, and the provision of this eccentric and its recessdoes not materially add to the cost of production of the lock nut, as compared to the ordinary plain dual nuts commonly employed, as they may be formed in the facing operation by simply providing for the eccentric chucking ofthe blanks from which the members are cut lduring the facing operation; and the securing of continuity in the threads of the members may be easily attained by proper setting of the taps or threading machines by Which the threads are cut With that object in view.

p The advantages resulting from the simple nature of the device and the fact that it is free from auxiliary mechanisms or attachments are mostly obvious and become increasingly evident when the first uses to Which it may be put are considered, as it will be quite apparent that the device is applicable in any position and for any purpose ivhere an ordinary nut may be employed.

lVith regard to the drawing, it is pointed out that the exaggerated nature thereof is simply intended for purposes of illustrating. the tendency of the parts to assume certain positions and is not intended to indicate the actual positions assumed thereby, precise illustration of such positions not being feasible, as, where the parts are machined to close limits, the actual movement especially hetWeen the threads oi the nut and holt would he to all practical intents and purposes praei ifally immeasurable.

This invention may be developed Within the scope ot the following claims Without deJ parting from the essential features ot the said invention, and it is desired that the specification and drawing he read as merel)7 illustrative and not in a limiting sense, except as neeessitated by the prior art.

llilhet I claim as my invention is:

l. A lock nut comprising` a pair oit threaded members, one niember having an eccentric recess around the bore thereof, a Cam carried by the other member and adapted to lit into said recess, said cam being,- also threaded internally in continuation of the threads in the member by which it is can ried, said men'ibers beingl so threaded that their threads are ui'u'tnzlllj,Y eoutil'lueiis When the cam is entered to its normal limit in said recess.

2. A look nut comprising a pair of thread ed members, one member having an eccentric recess around the bore thereof, u cam Carried by the other member and adapted to tit into said recess, said cam being,` also threaded internally in continuation of the threads in the member by which it is earried, said members being` so threaded that their threads are mutually continu-ous when the cam is entered to its normal limit in said recess, said cam being slightly less in thicl ness thun the recess whereby one of ss'd member may he turned to break the continiiitj-,fv or the threads and to create pressure between the eam and the Wall ot said recess.

In testimonyv whereof I aliix my signature.

JOHN MADDEN. 

